Microendodontics ultrasonic surgical dental tool having water port and method of making same

ABSTRACT

A dental tool for use with an ultrasonic transducer, the tool comprises a substantially elongate tool defined by a shaft having a proximal end with a coupling attachment at the proximal end for attachment to an ultrasonic transducer, and a distal end having a tip configured for performing a dental procedure, and a fluid passage extending from the proximal end to a port configured and positioned to direct fluid onto the tip.

FIELD OF THE INVENTION

[0001] This invention relates generally to ultrasonic dental tools andpertains more particularly to special micro endodontic ultrasonicsurgical and dental tools having a water port.

BACKGROUND

[0002] In the last four to five years microdentistry began to develop.Microdentistry is the performing of dental surgery and procedures withvery small tools under a microscope. As an example, in the preparationof root canals, it has been found that the tool must be very small inorder to work in the small canal areas. Such small tools must also bevery strong and touch and able to withstand and/or easily dissipateand/or resist heat.

[0003] In recent years ultrasonic tools have been developed which manydental surgeons have begun to use for many operations on teeth, bones,and soft tissue including dislodging and removal of dental material.These ultrasonic tools have been found to be particularly useful formicrodentistry and particularly for use in root canals. Tools for thispurpose must be small, hard, durable and heat resistant in order tosatisfactorily perform their function. They must also be flushed with afluid such as water to dissipate heat and flush away debris.

[0004] Recent years have seen greater use of ultrasonically poweredinstruments for the preparation of root canals. Examples ofultrasonically powered instruments of this type for the preparation ofroot canals are disclosed in U.S. Pat. No. 4,019,254, issued Apr. 26,1977 to Malmin, U.S. Pat. No. 5,094,617 issued Mar. 10, 1992 to Carr andPCT Publication WO 86/05967. With the exception of the first mentionedpatent, all tools are formed with a shaft tapered to a point. Morerecent examples of improved tools are disclosed in the applicant'srecently issued U.S. Pat. No. 5,836,765, issued Nov. 17, 1998, and U.S.Pat. No. 5,868,570 issued Nov. 12, 1998 to Hickok.

[0005] Most dental tools and work areas are cooled with a continuousstream of water during use. Cooling in this manner is not alwayspossible, particularly when working in certain small confined areas suchas root canals, and in most instances this form of cooling isinconvenient.

[0006] In the past, fluid such as water has been supplied to the cuttingtool by means of either a separate water supply such as a wand or thelike, or a supply through or from the adjacent power unit. The toolsnormally used with ultrasonic generators are typically very small andmust be hard and durable to withstand the high energy delivered by theultrasonic generator. Due to the size and the materials from which thetools are made, it has not been possible to provide a through the toolfluid supply to the tool and word area.

[0007] One example of an earlier dental tool having a fluid supply tothe tip is U.S. Pat. No. 3,924,335 dated Dec. 20, 1975, The patentdiscloses a metal or plastic transmission member which has a water feedto be used as a dental prophylaxis unit for removing deposits from toothand gingival surfaces. However, this tool is not suitable formicrodentistry.

[0008] U.S. Pat. No. 4,193,196 discloses a fluid supply unit for dentalinstruments wherein an instrument is shown with flow through tip. Thistool is not disclosed as suitable for microdentistry.

[0009] U.S. Pat. No. 5,733,119 discloses a dental tool having fluidsupply port in the hub of the tool. These tools of the prior art cannotbe made sufficiently small to function as a microdentistry tool andprovide the fluid port in the shaft of the tool at the working tip.

[0010] Therefore, there is a need for an improved ultrasonic dental toolformed of a suitable strong, flexible and durable heat resistantmaterial with suitable fluid port for microdentistry.

[0011] Another drawback to these tools is that they are attached anddetached from the hand piece of the ultrasonic generator by means of athreaded connection requiring a wrench or other special tool. This isparticularly inconvenient because several different shape tools arefrequently required during any particular operation.

[0012] Therefore, there is also a need for an improved ultrasonic dentaltool having a quick attach connector for microdentistry.

SUMMARY OF THE INVENTION

[0013] A primary objective of this invention is to provide an improvedultrasonic dental tool having a tip that is formed of durable highstrength heat resistant material and has a port for delivery of fluid tothe tip.

[0014] Another objective is to provide a tool of a suitable materialthat can be made small enough for MICROENDODONTICS that has provisionfor delivery of a fluid to the tip.

[0015] In accordance with a primary aspect of the present invention adental tool for use with an ultrasonic transducer comprises asubstantially elongate tool defined by a shaft having a proximal endwith means for attachment to an ultrasonic transducer, and a distal endhaving a tip configured for performing a dental procedure, an fluidpassage extending from the proximal end to a port positioned andconfigured to direct fluid on the tip.

BRIEF DESCRIPTION OF DRAWINGS

[0016] The objects, advantages and features of this invention will bemore readily appreciated from the following detailed description, whenread in conjunction with the accompanying drawing, in which:

[0017]FIG. 1 is a side elevation view of an ultrasonic dental toolconstructed in accordance with a preferred embodiment of the invention;

[0018]FIG. 2 is a front elevation view of the tool of FIG. 1;

[0019]FIG. 3 is a side elevation view of an alternate embodiment of anultrasonic dental tool;

[0020]FIG. 4 is a front elevation view of an another embodiment of anultrasonic dental tool;

[0021]FIG. 5 is a side elevation view illustrating an early step in themachining process of making tools in accordance with the invention;

[0022]FIG. 6 is a view like FIG. 5 illustrating an early step in themachining process of making tools in accordance with the invention;

[0023]FIG. 7 is a view like FIG. 6 illustrating a further step in themachining process of making tools in accordance with the invention;

[0024]FIG. 8 is a view like FIG. 7 illustrating a still further step inthe machining process of making tools in accordance with the invention;and

[0025]FIG. 9 is a view like FIG. 8 illustrating one of the final stepsin the machining process of making tools in accordance with theinvention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

[0026] The present invention is described with reference to preferredembodiments of the invention as illustrated in the drawings. While thisinvention is described in terms of the best mode for achieving thisinvention's objectives, it will be appreciated by those skilled in theart that variations may be made in view of these teachings withoutdeviating from the spirit or scope of the invention.

[0027] Referring to FIGS. 1 and 2 of the drawings there is illustratedan exemplary embodiment of a tool for dental surgical operations, inaccordance with the present invention, designated generally by thenumeral 10. The tool 10 is devised to get water or fluid to the workingedge of the surgical tip of endodontic work tool. The tips areconstructed with a tip on the order of one sixty-fourths inch indiameter at the point versus about one sixteenth of an inch for priorart tools. For this reason the tools are constructed of a medical gradetitanium alloy or a stainless steel alloy.

[0028] The inventor has found that titanium, which is not normallyconsidered a tool material, performs well as a dental tip, particularlyfor use ultrasonic generators. Suitable titanium materials are coveredin more detail in the inventors U.S. Pat. No. 5,836,765 granted Nov. 17,1998, which is incorporated herein by reference as though fully setforth. The tool may also be made of either 17-4 PH or 13-8 MO stainlesssteel. The tool as shown may be detachably connected to an ultrasonicvibrator or transducer (not shown) of generally well-known conventionalconstruction for carrying out microdental surgical procedures.

[0029] The tool, as illustrated, comprises an elongated shank havingconnecting means 12 at a proximal end. The connection means is shown inthe form of a threaded socket for threadably mounting on the end of ashaft and having a flat 14 on each side for engagement by a wrench orthe like for threadably tightening and loosening the tool.

[0030] The tool is formed with an elongated tapered shank or shaft 16which has a distal end portion 18 which is curved away from the shank toform what is commonly called a tip. The tip as used herein means thatportion of the tool between the curve or bend at 20 and the point 24.This tip portion is curved or bent at 20 in a direction away from theaxis of the shank at an angle of preferably about 75-85°, extending awayfrom the proximal end. This tip portion is the cutting or workingportion of the tool. The tool is designed primarily to perform rootcanals which are preferably performed from the root end of the tooth.These tools as provided herein enable the performance or an operationwherein the tooth is removed, the root canal work performed and thetooth reinstalled. This procedure must be carried out in less than tenminutes in order for the tooth to survive.

[0031] The tool is formed with a fluid outlet port 22 which communicatesfluid via an elongated axial passage from the proximal or connecting endof the tool. The outlet port 22 is positioned and configured to directfluid such as water onto the tip 18 and into the working area to flushdebris therefrom. The port may be positioned closer or further away fromthe bend 20 to achieve the desired placement of the fluid: As can beseen the tip extends in front of the outlet port.

[0032] The shank portion 16 extends outward from the connecting collar12 and is of a generally uniform taper in a manner, as illustrated. Theshank portion or section 16 of the shaft tapers gradually down to adistal or working end portion 18, or tip, which may have a sharpenedpoint or other form. This portion 22 is the primary working portion andmay have a length of from about one eight (⅛) to about three sixteenth({fraction (3/16)}) inch or three to about five mm. When constructed ofstainless steel this portion typically has a diameter of about 0.015 toabout 0.0250 inches or about 0.4 to 0.6 mm when made of stainless steelcalled for herein. The length can also be extended up to about 25 mm andthe diameter reduced about 0.015 inches or 0.4 to 0.6 mm whenconstructed of titanium.

[0033] Referring to FIG. 3, an alternate embodiment of an ultrasonictool is illustrated, designated generally at 26 and comprising anelongated shank 28, having connecting means or hub 30 at a proximal endwith the shank tapering down at a reduced diameter from the connectinghub with a substantially uniform taper along a shaft to a tip 32. Theshaft is formed with a bend at 29 between the hub 30 and the tip 32. Afluid outlet port 34 communicates fluid as in the prior embodiment viaan elongated passage from the proximal or connecting end of the tool tothe tip. The outlet port 34 is positioned and configured to direct fluidsuch as water onto the tip 32 and into the work area. The port, asillustrated, is shown positioned closer to the bend than in the priorembodiment for desired placement of the fluid. This tool may be used toperform any number of dental procedures and may be hardened or coatedwith suitable means for roughening or the like to create an abrasivesurface, if desired.

[0034] Referring to FIG. 4, another embodiment having a complex curvedconfiguration is illustrated and designated generally by the numeral 36having a connecting hub 38 with an elongated tapered shaft 40 down to apointed tip 42 extending upward at an angle to close to 90° from theaxis of the shaft 40. The angle of the tip may vary from less than 90°to greater than 90°, such as from about 75 to about 90 degrees, asdesired. The shaft 40 is provided with a complex set of bends orcurvatures at 44 and 46 between the hub and the tip. The complex curvedconfiguration enables the tool to reach difficult areas within the oralcavity. The shaft can have any number of bends and configurations suchas disclosed in the inventors prior U.S. Pat. No. 5,868,570 incorporatedherein by reference. This tip may also be suitably roughened and coatedas necessary to perform the necessary function.

[0035] The applicant has devised a novel method of making the tools inaccordance with the present invention. Referring to FIG. 5, an earlystep in the process is illustrated wherein a suitable bar stock 48 ofsuitable material from which to make the tool is selected and mounted ina chuck in a lathe extending through a guide bushing 50. The bar stockis preferably cylindrical with a central bore 52 extending the lengththereof. The bar stock which has a diameter of about 0.187 inch or 3.5mm with a central bore of about 0.020 inch or 0.5 mm is placed in thechuck of the lathe extending through the guide bushing with a length ofthe stock extending beyond the end of the guide bushing. A small taperedportion 54 is turned by a cutting tool 56 on a forward end of the barstock to establish a bend point and the location of the fluid port.

[0036] Referring to FIG. 6, the turned end portion 54 is bent by a tool58 out of alignment with the axis of the elongated stock. The taperedportion is bent off-center by the bending tool to allow the central holeor bore to run out the side of the bar when the bar is further turned toform the shaft of the tool.

[0037] The outer end of the stock is then turned with the cutting tool44 to form a tapered section. 48 which forms a tip of the tool, as shownin FIG. 7. As the tapered tip of the shaft is formed, the bore runs outforming a port 62. The location of the bend as in FIGS. 5 and 6establishes the location of the port from the point 64 of the workpiece. Thereafter, the turning of the dental tool is completed in thelathe so that the general shape and size of dental tool is finished asillustrated in FIG. 8. An elongated shaft 66 is formed with a hub 68having flats 70 for engagement by a wrench. The hub is then formed witha bore that is threaded to mount on a transducer shaft. The tip is thenbent at the appropriate point in front of the port as seen in FIG. 8.The tool is then severed from the end of the stock by a cutoff tool 72.Some or all of the bending may take place while in the lathe.Alternatively, all of the bending can be performed after the tool blankis removed from the lathe.

[0038] The tool blank is shaped to the desired final configuration bybending and forming the tip so that fluid flows from the port onto thetip at the desired position. A variety of other bends may be made in theshaft or shank to provide the desired final configuration. The tool mayundergo other treatments including roughening and heat treating asdiscussed hereinafter.

[0039] These tools may be modified in any number of ways to provide thebest structure and features for performing various procedures, includingscaling, drilling, root canal and the like. Various heat and othertreating and hardening processes may also be utilized in preparing thevarious tools for their ultimate intended purposes. Likewise, variouscoatings may be applied to the tip to achieve its purpose.

[0040] The tool is preferably constructed of a good medical grade ofstainless steel or a titanium alloy of a medical grade. Medical gradealloy means a material that may be used in contact with food and with apatients body without undergoing a chemical reaction. A titanium alloythat the inventor has found preferable in the present application isidentified as 6AL/4V ELI & CP Grade 4 and is available from PresidentTitanium of Hanson, Mass. The inventor has found this material to besufficiently hard, durable and flexible to resist breakage under use. Itwas also found to withstand heat for short durations of use in theabsence of a cooling fluid without burning or melting. Tools can be madesmaller with the titanium alloys than have ever been achieved beforewith the stainless steels. They can be made very small with very smalltips that will withstand the rapid buildup of heat normally encounteredin orthodontal applications. Other titanium alloys may also be used.

[0041] The above-described alloy has about 5.5 to about 6.5% aluminum,about 3.5 to about 4.5% vanadium, about 0.25% of iron, about 0.05%nitrogen, about 0.08% of carbon and about 0.015% of hydrogen. Thismaterial has an ultimate tensile strength of about 130,000 psi, and ause strength of about 120,000 psi. It has a Rockwell-C hardness of30/34. While this material has been known for uses such as for surgicalappliances and implants, orthopedic implants and the like, applicant hasfound no suggestion of its use in dental tools, as set forth herein.

[0042] Other titanium alloys and their properties and specificationswhich may be suitable for the herein use are available from theaforementioned supplier. For example 6AL/4V, CP Grade 2 and CP Grade 4.Specifications for machining, heat treating and other technical data andspecifications for manufacture and use of various alloys of titanium isavailable from President Titanium in a Machining and Technical datahandbook. In many applications, applicant has found that these materialscan be used for the tools herein without the necessity for heattreating.

[0043] The applicant has found that the titanium material discussedherein is suitable for a long line of ultrasonic dental tools, as willbe hereinafter described. Ultrasonic tools for dental work must be verysmall, durable and heat-resistant. Such tools must also be easilymatched or tuned to an ultrasonic generator.

[0044] A modification may be made wherein the ultrasonic dental tip isprovided with a roughened area extending from near curved radius portionto pointed end. The roughened area provides a coarse abrasive surfacethat will cut along any part of the roughened surface.

[0045] Preferably the roughing of the surface is performed by sandblasting the desired area with a microetcher or microblaster usingapproximately 400 grit powder. A suitable choice for such a sandblasteris provided by Danville Engineering Inc., of Danville Calif., and isavailable by the model name of “S-2 Precision Microsandblaster.” It ispreferable to operate the sandblaster by supplying pneumatic pressure ofabout 60-120 pounds-per-square inch, although it will be apparent to oneskilled in the art that a suitable hydraulic pressure could be provided.

[0046] The roughening of the tool surface is preferably carried outafter any hardening and before any coating process. The roughening is aless expensive process than coating with diamond particles. It alsoenables the construction and preparation of more precise and accuratetips.

[0047] Referring to FIGS. 9 through 11, a quick connect adaptor forenabling the quick changing of the dental tools is illustrated. Thequick change coupling assembly according to the invention comprises anadaptor piece 80 having a hub with a threaded socket 82 adapted to fit ahand piece of an ultrasonic generator. The adaptor 80 is provided with aforwardly axially extended elongated shaft 84 having a tapered tip orend 86 that function as a cam as will be described. A water passage 88is formed in and extends from the coupling socket 82 through the tip 86of the shaft to communicate with a passage in a tool. A threaded stud 90is formed on the end of the connecting hub 80 at the juncture of themember 84 for cooperating with threads on a connector sleeve hereinafterdescribed. The adapter piece 80 may be formed as an integral part of thehand piece of the ultrasonic generator.

[0048] A connector sleeve 92 as best illustrated in FIG. 11 has a hubformed with a threaded socket 94 at one end and an elongated splitsleeve member 96 extending axially thereof. The sleeve 96 has anelongated internal generally cylindrical bore 98 with a generallyconical shaped end portion 100 that acts as a cam. The wall of thesleeve is formed with a slot only one of which 102 is shown on oppositesides thereof. These slots enables the sleeve to expand as will besubsequently explained.

[0049] The outer surface of the sleeve is formed with a plurality ofannular grooves 104 alone the length thereof to aid in gripping theinternal cylindrical wall of the mounting socket of the dental tool. Anannular groove 106 is provided with an elastromeric o-ring 108 toposition the ultrasonic tool as will be explained.

[0050] Referring now specifically to FIG. 9, an ultrasonic dental tool110 has a hub 112 with a coaxial generally cylindrical mounting socket114. An annular groove 116 is provided or formed in the innercylindrical mounting socket bore of the tool to receive the elastromerico-ring 108 when the socket is forced onto the sleeve 92. In operationthe sleeve 92 mounted on the shaft 84 with threads 94 engaging threads90 backed off from the threads 90 on the adaptor 80 until the forwardconical or cam portion 100 thereof backs off from the forward conicalshape cam 86 of the member 84. It will be apparent that only one of thecam surfaces 86 and 100 may be required. In other words either one ofthe cams may be present and the other absent. The hub of a tool isplaced on the outer surface of the sleeve until the annular groove 116snaps over the o-ring 108. Thereafter the sleeve 92 is rotated by handthreading the threads 94 onto the threaded portion 90 until the sleeveis cammed and expands into tight engagement with the internal bore 114of the hub of the tool. This adapter assembly enables the quickdetachable connection and removal of tools on a hand piece of anultrasonic generator.

[0051] While I have illustrated and described my invention by means ofspecific embodiments, it is to be understood that numerous changes andmodifications may be made therein without departing from the spirit andthe scope of the invention as defined in the appended claims

I claim:
 1. A dental tool for use with an ultrasonic transducer, thetool comprising: a substantially elongate tool defined by a shaft havinga proximal end with attachment means at said proximal end for attachmentto an ultrasonic transducer, and a distal end having a tip configuredfor performing a dental procedure; and a fluid passage extending fromsaid proximal end to a port configured and positioned to direct fluidonto said tip.
 2. The tool of claim 1, wherein said shaft has a bend atsaid distal end distal end forming said tip to extend at an angle tosaid shaft and said port directs fluid from a position on said shaftonto said tip.
 3. The tool of claim 2, wherein said tip extends at anangle of between 75 and 90 degrees to said shaft.
 4. The tool of claim3, wherein said port is closely adjacent said bend forming said tip andon the same side of said shaft as said tip.
 5. The tool of claim 4,wherein said shaft has at least one bend between said attachment meansand said bend forming said tip.
 6. The tool of claim 4, wherein said tipis formed with a sharp point having a diameter of about {fraction(1/64)} inch.
 7. The tool of claim 4, wherein said shaft has acontinuous taper from said attachment means to said tip.
 8. The tool ofclaim 1, wherein said shaft has a continuous taper from said attachmentmeans to said tip.
 9. The tool of claim 8, wherein said shaft has a bendat said distal end forming said tip extending at an angle to said shaftand said port directs fluid from a position on said shaft adjacent saidbend onto said tip.
 10. The tool of claim 9, wherein said tip extends atan angle of between 75 and 90 degrees to said shaft.
 11. The tool ofclaim 9, wherein said tip is formed with a sharp point having a diameterof about {fraction (1/64)} inch.
 12. The tool of claim 9, whereintitanium is an alloy containing about three and one-half to about fourand one-half percent vanadium.
 13. The tool of claim 9, wherein saidshaft has at least one bend between said attachment means and said bendforming said tip.
 14. The tool of claim 13, wherein said shaft hasmultiple bends between said attachment means and said bend forming saidtip.
 15. The tool of claim 8, wherein said tip is roughened by minutedepressions in the body of the shaft at least in an area adjacent thepoint.
 16. The tool of claim 1, wherein said tool has a hub with agenerally cylindrical mounting socket and further comprising a quickconnect connector comprising: a shaft adapted for attachment to a handpiece of an ultrasonic generator; an expandable sleeve adapted formounting on said shaft and extending into said socket; and a cam memberon one of said sleeve and shaft operatively camming said sleeve intoengagement with said mounting socket.
 17. The tool of claim 16, whereinsaid shaft and said sleeve have threads for moving said sleeve axiallyalong said shaft to affect said camming.
 18. A method for making adental tool for use with an ultrasonic transducer using a lathe, themethod comprising: providing a substantially elongate stock materialdefining a shaft having a distal end section with a tip and a centralbore; placing the stock material in a guide bushing of the lathe;bending the distal end section of the stock material to offset thecentral bore outlet with respect to the axial orientation of the centralbore; and turning the stock material in the lathe at the distal endsection, thereby producing a dental tool with a working tip and anoutlet port to direct fluid onto said tip.
 19. The method of claim 18,wherein the step of turning the stock material in the lathe includesforming a bend point in the shaft prior to the step of bending thedistal end section of the stock material bending the distal end includesforming a contra-angle portion curved outward in a first direction fromsaid axis at an angle of about fifteen degrees and curved outward in asecond direction across said axis at about forty-five degrees to saidaxis to said tip.
 20. The method of claim 19, wherein the step ofturning the stock material in the lathe includes forming attachmentmeans of the stock material at a proximal end and a continuous taperfrom said attachment means to said tip; said shaft has a continuoustaper from said attachment means to said tip.
 21. The method of claim20, including the further step of bending the distal end forming saidtip at an angle with respect the shaft.
 22. The method of claim 21,including the further step of roughening at least said tip by formingminute depressions in the body of the shaft at least in an area adjacentthe point.
 23. A quick change connector for a dental tool, comprising: agenerally cylindrical mounting socket on said tool; an elongate shaft ona hand piece of an ultrasonic generator; an expandable sleeve adaptedfor mounting on said shaft and extending into said socket; and a cammember on one of said sleeve and shaft operatively camming said sleeveinto engagement with said mounting socket.
 24. The quick changeconnector of claim 23, wherein said shaft and said sleeve have threadsfor moving said sleeve axially along said shaft to affect said camming.25. The quick change connector of claim 24, wherein said shaft and saidsleeve have each have a cam member thereon.
 26. The quick changeconnector of claim 23, wherein: said sleeve has an annularcircumferential member thereon; and said socket has a circumferentialgroove for engaging said circumferential member for positioning saidsocket.
 27. The quick change connector of claim 23, wherein: said sleevehas at least one annular circumferential groove thereon adapted toenhance gripping of said socket by said sleeve.